Salt and sand that trucks have dispersed along the edges of your yard stifle new sprouting grasses and prevent pre-emergents from binding chemically with topsoil, opening it up to weeds. Instead of raking, gently sweep the area 2 feet from the curb.

When replacing damaged turf, seed as early as possible. Then wait before putting down a pre-emergent. Pre-emergents preempt both weed and grass seeds from germinating. Once you see grass roots, two to three weeks should be enough before you apply an eco-friendly pre-emergent.